The invention relates to an apparatus at a spinning preparation machine, for example a card, card drawing mechanism, draw frame, combing machine or the like, for changing sliver cans. In one known arrangement, sliver is delivered by a rotary plate and deposited in a sliver can, the arrangement comprising means for moving a full sliver can away from the region of the rotary plate, means for subsequently bringing in an empty sliver can from a position of readiness to the region of the rotary plate, and an intermediate storage means, for example a holding plate, arranged to be brought in to the rotary plate during changing of the sliver cans.
A known apparatus (DE 36 18 857 A) has an intermediate storage means in the form of a plate, which can be pivoted about an axis from a pivoted-out position to a position under the rotary plate. The plate is provided with a drive for the pivoting, preferably a pneumatic press. After separation of the sliver, which continues to be supplied, the intermediate storage means in the form of a plate is pivoted into a position under the rotary plate so that the separated sliver is caught by the plate. When the empty sliver can is placed under the rotary plate, the plate is moved out again. When the plate is moved out, which is preferably carried out with a jerking movement, the sliver deposited on the plate in the form of sliver cycloids is thrown off and transferred to the empty sliver can. In order to facilitate that throwing-off, the plate has a slight inclination such that the edge which is at the front while moving away from the region of the rotary plate is closer to the rotary plate. It is disadvantageous that the sliver continuing to run onto the plate becomes heaped into a column of sliver in undesirable manner, which results in its piling up in the empty can and consequently in a lack of uniformity. In addition, problems of space in the height direction also arise as a result. Finally, it is disadvantageous that can changing is not possible at maximum speed or in the region of the maximum speed without disadvantageous piling up of the sliver.
It is an aim of the invention to provide an apparatus of the kind described at the beginning that avoids or mitigates the mentioned disadvantages and that especially avoids disadvantageous piling up of the sliver on the intermediate storage means and/or in the sliver can and allows can changing at maximum sliver production speeds.
The invention provides a can-changing apparatus for a spinning preparation machine, comprising:                a filling station at which a sliver can can be filled with fibre sliver from a sliver delivery device;        a device for removing a full can from the filling station;        a device for delivering an empty can to the filling station; and        an intermediate storage device which can be positioned to collect sliver delivered during changing of the cans, in which the intermediate storage device is arranged to be driven such that it is movable beneath the delivery device whilst collecting the sliver.        
As a result of the fact that the intermediate storage means is moved during deposition, disadvantageous piling up of the sliver is avoided both on the intermediate storage means and in the empty can. It is especially advantageous that can changing is possible at especially high sliver production speeds, ideally without—or without substantially—reducing the delivery speed of the sliver-producing machine. As a result of use of the intermediate storage means, operation at a higher delivery speed is possible during can changing. Because there exists a direct relationship between variations in delivery speed and the quality obtained during such variations, this increases both the efficiency of the machine and the quality of the sliver produced during can changing. In particular, disadvantageous drafting effects in the sliver are reduced or avoided.
In one preferred embodiment, the sliver can is an oblong can. Advantageously, the movement of the oblong can during deposition is a rectilinear, reciprocating movement. In that case, the movement of the intermediate storage means during changing of the oblong can is preferably a rectilinear, reciprocating movement. Advantageously, the intermediate storage means is arranged to be brought in in a direction perpendicular to the longitudinal axis of the oblong can.
In another preferred embodiment, the sliver can is a round can, and the movement of the round can during deposition is a rotary movement. In that case, the movement of the intermediate storage means during changing of the round can is preferably a rotary movement.
Advantageously, the intermediate storage means is arranged to be brought in in the direction towards the delivery device and away therefrom. Advantageously, the intermediate storage means is arranged to be brought into a position underneath the delivery device. Where the cans are oblong cans, the intermediate storage means, for example holding plate or the like, is advantageously substantially oblong. Where the cans are round cans, the intermediate storage means, for example holding plate or the like, is advantageously substantially round.
Advantageously, a clearing element or the like is provided, which can be used for clearing the sliver off from the intermediate storage means. Advantageously, the clearing element and the intermediate storage means are arranged to be moved relative to one another. Preferably, the clearing element is stationary. Advantageously, the clearing element is arranged between the sliver delivery device and the intermediate storage means. Advantageously, the clearing element is capable of clearing the sliver off from the upper surface of the intermediate element. In use, it is preferred that the cleared sliver drops into the empty can, for example, onto a lifting bottom of the empty can. Advantageously, a sliver separating device is provided. Advantageously, the sliver separating device is capable of separating the sliver deposited in the full can from the subsequently supplied sliver. For example, before deposition, there may be produced, in the sliver, a thin location from which the sliver tears off when the full can is moved away. Advantageously, the height of the intermediate storage means is adjustable relative to the sliver delivery device and/or the sliver can.
Where oblong cans are used, during change-over, the sliver delivery device is advantageously located at that end face of the full can which is next to the empty can. The full can may be moved away from and/or the empty can subsequently brought in perpendicular to the longitudinal direction of the can (via the long wall surface). Instead, the full can may be moved out and/or the empty can subsequently brought in in the longitudinal direction of the can (via the short wall surface).
It is preferred that, during changing of the sliver cans, sliver that continues to be supplied from the delivery device is deposited on the intermediate storage means.
The invention also provides an apparatus at a spinning preparation machine, for example a card, card drawing mechanism, draw frame, combing machine or the like, for changing sliver cans, wherein sliver is delivered by a rotary plate and deposited in a sliver can, comprising means for moving a full sliver can away from the region of a rotary plate, comprising means for subsequently bringing in an empty sliver can from a position of readiness to the region of the rotary plate and comprising an intermediate storage device, for example a holding plate, arranged to be brought in to the rotary plate during changing of the sliver cans, wherein there is associated with the intermediate storage device a drive element, which is capable of imparting to the intermediate storage device during changing of the sliver cans a movement which substantially corresponds to the movement of the sliver can during deposition of the sliver.